Foodborne Illnesses: The 10 Most Common Foodborne Diseases and Examples

Foodborne illnesses, also known as food poisoning, occur when people consume food contaminated with pathogenic microorganisms or their toxins. These contaminants are often invisible — food may look, smell, and taste normal — but can cause serious gastrointestinal symptoms such as abdominal pain, diarrhea, nausea, vomiting, and fever.

The current food safety and quality control systems, both in primary production and processing and marketing in developed countries, ensure a high level of consumer protection in food matters. Therefore, the incidence of outbreaks of infections such as those mentioned below can be considered relatively rare. Furthermore, alert networks such as the RASFF database (Rapid Alert System for Food and Feed), the most important information exchange tool at the European level, guarantee swift action by authorities and various operators in the event of alerts. Below is a clear list of the 10 most common Foodborne diseases, including their causes, symptoms, and prevention measures.

List of the 10 Most Common Foodborne Illnesses

1. Salmonella

Its main source is the intestinal tract of animals, primarily birds and pigs, and it can contaminate raw meats, raw chicken, raw seafood, or eggs, among others. Symptoms may include nausea, vomiting, abdominal cramps, diarrhea, fever, and headache, lasting between 1 and 2 days or longer. Salmonella is sensitive to heat and is killed by heating (above 70°C). Raw foods or those that have been undercooked, along with cross-contamination that occurs when cooked products come into contact with raw or contaminated ones (such as cutting boards), are the main causes of infection. Therefore, proper cooking and hygiene during food handling can greatly prevent infections caused by Salmonella.

2. Listeria monocytogenes

Listeriosis is a disease caused by consuming food contaminated with this bacterium. It is a worldwide infection but is rarely diagnosed. It usually presents with fever, muscle aches, and sometimes gastrointestinal symptoms such as nausea or diarrhea. If the infection spreads to the nervous system, it manifests as meningoencephalitis with fever, severe headache, neck stiffness, loss of balance, or seizures. Foodborne transmission appears to be the most common cause, with ingestion of raw foods such as raw meats and vegetables, as well as processed foods that become contaminated after processing, such as soft cheeses, deli meats, or unpasteurized dairy products and foods made from unpasteurized milk.

3. Norovirus

Noroviruses can spread rapidly from person to person in enclosed, crowded places and can be a major cause of gastroenteritis acquired in restaurants and food-serving establishments if the food is contaminated. The types of foods most frequently linked to norovirus outbreaks include leafy greens (such as lettuce), fresh fruits, and live shellfish. However, any food served raw or handled improperly after cooking can become contaminated with norovirus. It is contracted by consuming contaminated foods and liquids, contaminated surfaces or objects, or direct contact with an infected person. Symptoms usually consist of diarrhea, vomiting, nausea, stomach cramps, and others such as low-grade fever, chills, headache, muscle aches, and a general feeling of fatigue. Norovirus illness is generally not serious, and most people recover within 1 to 2 days.

4. Escherichia coli

There are several types of E. coli bacteria, and most are not harmful to humans, but some can cause illness. It is a bacterium that lives in the intestines of most healthy mammals and also in stagnant water. Although there are various types that are not harmful to humans, others cause infections of the excretory system, meningitis, pneumonia… and symptoms include stomach pains, some fever, gas, loss of appetite, vomiting, and diarrhea, occurring 24 to 72 hours after the bacteria enters the intestines. Some ways to become infected include eating contaminated raw or unwashed fruits and vegetables, drinking unpasteurized milk, eating raw or undercooked meat, drinking contaminated water, etc.

5. E. coli O157:H7

Although Escherichia coli O157:H7 is actually one of hundreds of strains of the Escherichia coli bacterium, it produces a potent toxin and can cause serious illness. Infection often leads to acute diarrhea with little or no fever and occasionally kidney failure. Transmission has been associated with consumption of contaminated and inadequately cooked beef. Among other known sources of infection are consumption of Brussels sprouts, lettuce, salami. Person-to-person contact is also a form of transmission. Consumers can prevent infection by cooking meat thoroughly and avoiding unpasteurized milk as well as practicing good hand hygiene.

6. Toxoplasma gondii

The cause of toxoplasmosis is a parasite called Toxoplasma gondii, one of the most common infections worldwide that often go unnoticed. Symptoms, when they occur, tend to resemble those of the flu. Normally, active infection occurs only once in a lifetime. Although the parasite remains in the body indefinitely, it generally does not cause harm. When contracted by a pregnant woman, it can endanger the health of her future baby. However, the risk and severity of the baby’s infection depend in part on when the mother contracts the infection. In babies, it can cause eye infections, hearing loss, mental retardation, or learning disabilities. It can also cause spontaneous abortion. The most common way to contract this parasitic infection is through exposure to cat feces or by eating raw or undercooked meats contaminated with the parasite, as well as in goat’s milk, raw eggs, and insects.

7. Clostridium perfringens

The main cause of its proliferation in food is keeping the food warm after preparation. A small number of organisms may be present after product manufacture, and they can multiply during storage or when large quantities of food are prepared many hours in advance. The highest risk originates from cross-contamination, which occurs when cooked food comes into contact with raw or contaminated ingredients, or with contaminated surfaces (such as cutting boards). Meats and their derivatives are most commonly involved. Symptoms include severe abdominal cramps and diarrhea. Normally, this illness disappears after 24 hours.

8. Campylobacter

It can be found anywhere but mostly in the intestines of numerous animals and even humans. It can be contracted by consuming unpasteurized milk, raw or undercooked meats or poultry, and other contaminated foods as well as contaminated water. Symptoms of infection occur between 2 to 10 days after consuming the infected food and include fever, abdominal pain, and diarrhea (sometimes with blood), and can last for a week. If it becomes complicated, it can lead to meningitis, urinary tract infections, and possibly arthritis and rarely Guillain-Barré syndrome, an unusual type of paralysis.

9. Clostridium botulinum

Foodborne botulism is the name of the disease (currently classified as food poisoning) caused by consuming foods containing the neurotoxin produced by C. botulinum. Symptoms occur between 18 – 36 hours after ingesting the toxin-containing foods. Symptoms of intoxication include weakness and dizziness, usually followed by double vision and progressive difficulty speaking, as well as difficulty breathing, muscle weakness, abdominal distension, etc. The types of foods involved with botulism vary according to preservation and eating habits, and any food is suitable for the growth of the microorganism and the production of the toxin.

10. Bacillus cereus

The symptoms caused by contracting this bacterium B. cereus are very similar to those caused by Clostridium perfringens. The onset of watery diarrhea, abdominal cramps, and pain occurs after 6-15 hours of consuming the contaminated food. Likewise, diarrhea may be accompanied by nausea, although vomiting rarely occurs. In most cases, symptoms persist for 24 hours. A wide variety of foods including meats, milk, vegetables, and fish, as well as rice-based products, starchy foods, pastas, and cheeses are also associated with this type.

Why Understanding Foodborne Diseases Is Important

Knowing the most common foodborne illnesses helps consumers and food producers improve food handling practices, reduce contamination risks, and protect public health. Modern food safety systems, rapid alert networks, and scientific testing continue to play a key role in preventing outbreaks and ensuring food quality.